Monthly Archives: January 2017

POWER PLANT: Two Ishikawajima Ne-20 turbojet engines, rated at 475 kp each

PERFORMANCE: 433 mph at 32,800 ft (estimated)

COMMENT: Design work on the Nakajima “Kikka” – the only Japanese turbojet powered aircraft capable of taking-off on its own power, albeit only twice during World War II – began in September 1944. The enthusiastic reports on the progress of the Messerschmitt Me 262 twin-jet fighter received from the Japanese Air Attaché in Germany had prompted the Naval Staff to instruct Nakajima to design a single-seat twin-jet attack fighter based on the German Me 262.
The aircraft externally resembled the Me 262 but was smaller. Two turbojets were mounted in separate nacelles under the wing to allow the installation of engines of various types. Provisions were made for folding wings, to enable the aircraft to be hidden in caves and tunnels and also for ease of production by semi-skilled labor. Initial plans to power the aircraft by two N-12 turbojet engines each delivering 340 kp thrust were refused due to insufficient thrust. Fortunately, photographs of the German BMW 003 axial-flow turbojet had been obtained and from these the Japanese were able to design a similar turbojet, designate Ne-20, offering a thrust of 475 kp. Completed in August 1945, the first “Kikka” made its maiden flight. Four days late the pilot aborted a take-off during the second flight, the accident being caused by mounting the two rocket-assisted-take-off (RATO) rockets at an incorrect angle. A second prototype (shown here) was almost ready for flight trials and eighteen additional prototypes and pre-production aircraft were ready in various stages of assembly when with the end of WW II the development of the aircraft was terminated (Ref.: 1).

COMMENT: To meet the growing production requirements, General Motors Corporation was asked to establish a second source for Grumman TBF-1 “Avengers” at its Eastern Aircraft division, already building the Grumman F4F “Wildcats”. The first contract was placed on March 1942, and deliveries began in November of the same year, this version being designated TBM-1. Grumman production continued until early 1944, with a total of 2,290. These were primarily of the TBF-1 or TBF-1C version. Eastern produced 2,882 TBM-1 and later went on to build 4,664 more powerful and improved TBM-3s (Ref.: 1).

The escort aircraft carrier CVE-106 “Block Island II” was laid down and launched as CVE-106 “Sunset Bay”. On July 1944 she was renamed “Block Island II” in honor of CVE-21 “Block Island I”, sunk by German submarine in June 1944.

COMMENT: Despite the total failure of the Messerschmitt Me 209 V4 and the disappointing performance of the Messerschmitt Me 309, the Messerschmitt design bureau was still determined to provide the successor of the Messerschmitt Me 109 in the Luftwaffe’s fighter arm and a competitor for Focke-Wulf’s Fw 190D and Ta 152 fighters. It was realized that no useful purpose could be served in attempting any further development of the original Messerschmitt Me 209, and it was decided, therefore, to produce an entirely new fighter design which, in order to accelerate development and subsequent production, was to use a large proportion of standard Me 109 components. The new fighter was designated Messerschmitt Me 209-II and was, in fact, a modernized, more powerful Me 109 and employed sixty-five per cent of the earlier fighter’s components. The Me 209-II adopted an exceptionally wide-track, inward retracting undercarriage. Another major change was the installation of a Daimler-Benz DB 603G with an annular radiator. Overall wingspan was substantially increased and the vertical tail surfaces were enlarged. The prototype for the Me 209-II, the Me 209 V5 (A-1), was flown for the first time on November and tests revealed that the aircraft processed an excellent performance and overcame most of the Me 109’s shortcomings. Shortages of the DB 603G engine resulted in a demand for the installation of the Junkers Jumo 213E liquid-cooled engine. Designated Me 209A-2 flight trials began in December 1943. By this time, however, the Focke-Wulf Fw 190D-9 was entering service and this fighter had a speed advantage of some 30 mph at altitude, and as the introduction of the Me 209-II would disrupt fighter deliveries at a critical phase of the air war, it was decided to discontinue the development of the Messerschmitt design (Ref.: 11).

COMMENT: The Mitsubishi J2M “Raiden” was a single-engine land-based fighter aircraft used by the Imperial Japanese Navy Air Force in World War II. The Allied reporting name was “Jack”. The J2M was designed to be a strictly local-defense interceptor, intended to counter the threat of high-altitude bomber raids, and thus relied on speed, climb performance, and armament at the expense of maneuverability. The J2M was a sleek, but stubby craft with its over-sized Mitsubishi Kasei engine buried behind a long cowling, cooled by an intake fan and connected to the propeller with an extension shaft.
Teething development problems stemming from the Kasei engine cooling system, and the main undercarriage members led to a slowdown in production. The first few produced J2M2s were delivered to the development units in December 1942 but severe problems were encountered with the engines. Trials and improvements took almost a year and the first batch of the serial built J2M2 was delivered in December 1943. Parallel with the J2M2, production of the J2M3 “Raiden” started. The first J2M3s appeared in October 1943 but deliveries to combat units started at the beginning of February 1944.The “Raiden” made its combat debut in June 1944 during the Battle of Philippine Sea. Several J2Ms operated from Guam and Saipan and a small number of aircraft were deployed to the Philippines.
Primarily designed to defend against the Boeing B-29 “Superfortress”, the lack of a turbocharger handicapped the aircraft at high altitude. However, its four-cannon armament supplied effective firepower and the use of dive and zoom tactics allowed it to score occasionally. Insufficient numbers and the American switch to night bombing in March 1945 limited its effectiveness (Ref.: 24).

COMMENT: The Douglas A-26 “Invader” was Douglas Aircraft’s successor to the A-20 “Havoc”, in British service known as Douglas “Boston”, and was one of the most successful and widely operated types flown by Allied air forces in World War II. It was a twin-engine light bomber and ground attack aircraft, was fast and capable of carrying twice its specified bomb load.
A re-designation of the type from A-26 to B-26 led to confusion with the Martin B-26 “Marauder”, which first flew in November 1940, about 16 months before the Douglas design’s maiden flight. Although both types were powered by the widely used Pratt & Whitney R-2800 “Double Wasp” eighteen-cylinder, double-row radial engine, they were completely different and separate designs. Roughly 5,300 Martin “Marauders”, originated in 1939, were produced twice as many in comparison to the Douglas design.
The Douglas XA-26 prototype first flew on July 1942. Flight tests revealed excellent performance and handling, but problems with engine cooling led to cowling changes and elimination of the propeller spinners on production aircraft. Repeated collapses during testing led to strengthening of the nose landing gear. The Douglas A-26 was originally built in two different configurations. The A-26B had a gun nose housed six to eight .50 caliber machine guns, officially termed the “all-purpose nose”, later commonly known as the “six-gun nose” or “eight-gun nose”. The A-26C’s “glass” nose, officially termed the “Bombardier nose”, contained a Norden bombsight for medium altitude precision bombing. The A-26C nose section included two fixed M-2 guns, later replaced by underwing gun packs or internal guns in the wings.
After about 1,570 production aircraft, three guns were installed in each wing, coinciding with the introduction of the “eight-gun nose” for A-26Bs, giving some configurations as many as 14 .50 in machine guns in a fixed forward mount. The A-26C nose section could be exchanged for an A-26B nose section, or vice versa, in a few man-hours, thus physically changing the designation and operational role. The “flat-topped” canopy was changed in late 1944 after about 820 production aircraft, to a clamshell style with greatly improved visibility. Alongside the pilot in an A-26B, a crew member typically served as navigator and gun loader for the pilot-operated nose guns. In an A-26C, that crew member served as navigator and bombardier, and relocated to the nose section for the bombing phase of an operation In most missions, a third crew member in the rear gunner’s compartment operated the remotely controlled dorsal and ventral gun turrets, with access to and from the cockpit possible via the bomb bay only when that was empty (Ref.: 24).

COMMENT: In February 1942 severe problems became obvious with the new twin-engine Messerschmitt Me 210, successor of the aging Messerschmitt Me 110. Due to longitudinal instability and lack of performance the series production was stopped and switched back to the inadequately Me 110. So Messerschmitt was forced to redesign the aircraft by lengthening the fuselage and adding more powerful engines what finally became the Messerschmitt Me 410. In the meantime a search was begun on a new design for a twin-engine heavy fighter.
Since beginning of 1939 Prof. A. Lippisch and his design staff was part of the Messerschmitt Company and was well known for many advanced and unorthodox projects. Among these was a design study, the Lippisch LiP.10, a fast, tailless, twin-engine bomber that incorporated many parts of the unsatisfactory Me 210. Independent to this Dr. Wurster from Messerschmitt’s design team was working on a similar project that officially was designated Messerschmitt Me 329. This aircraft was of tailless design and was to be constructed mainly from wood. This would save on strategic materials and keep the weight lower. The large area wing was swept back at approximately 26 degrees, and two Daimler-Benz DB 603 engines were buried in the wings, each driving a 3.4 m four-bladed pusher propeller. A large fin and rudder was mounted at the rear and a tricycle landing gear was provided. Other advanced touches included the pilot and navigator sitting tandem in a broad bubble canopy and a remote-controlled rear gun in the tail aimed via a periscope system from the cockpit. Performance comparison between the Lippisch Li P.10, the Me 329 and the Me 410 showed that the improvement of the Me 329 over the Me 410 was marginal. So development received a low priority, and while a full-scale glider mock-up was tested in the winter of 1944/5, work on the project was cancelled shortly after (Ref.: 16, 17).